Haikaru, King of Beasts

You have, "At the beginning of your upkeep, or whenever an opponent becomes announced (this excludes your knight), you may create a green
0/1 saproling creature token that has, "Sacrifice
this creature: Add {c} to your mana pool." and
"{3}: Prevent all damage that would be dealt this
turn by spells and permanents your opponents
control. You may use this ability once per game.
You may use this ability an additional time for
each announced knight."